The new discussion around weight loss doesn’t judge success by the numbers on the scale. Instead the focus is on losing inches without losing muscle, a combination that’s hard to achieve by cutting calories alone.

Why is maintaining muscle so important? Contrary to fat, which stores energy, muscles burn calories, which makes it a key player in keeping lost weight from coming back. It also preserves functional strength, which makes the chores of everyday life easier to accomplish. Yet traditional diets have been known to reduce lean body mass by 20-30 per cent.

The trouble with relying on both exercise and diet to lose unwanted weight is that both variables can be manipulated in thousands of ways. The Exercise Metabolic Research Group from McMaster University has been actively searching for the most effective combination of diet and exercise with their latest study bringing them one step closer to defining strategies for what Dr. Stuart Phillips, member of the Exercise Metabolic Research Group and Canada Research Chair in Skeletal Muscle Health, calls “high quality weight loss.”

The McMaster team divided 25 moderately active young men into two groups and manipulated their dietary and exercise habits for four weeks to see if they could get in shape, lose weight and preserve or gain muscle mass. Each of the men was provided with pre-packaged meals individually designed to disrupt energy balance by a reduction of a whopping 40 per cent fewer calories daily. Group 1 consumed 15 per cent of their calories from protein, 50 per cent from carbohydrates and 35 per cent from fat. Meals for Group 2 were made up of 35 per cent protein (three times the recommended daily allowance), 50 per cent carbohydrates and 15 per cent fat.

The protein was administered throughout the day in meals and in liquid form with one drink reserved for immediately after exercising. Neither group was aware of whether they were consuming the high or low protein diet.

As for the exercise, the young men reported to the gym six days a week where they performed a weight training circuit twice a week, a HIT (high intensity interval training) workout twice a week, an aerobic workout on the bike once a week and a plyometric (jump training) circuit workout once a week. In addition they were asked to accumulate 10,000 steps on days they weren’t in the gym.

At the end of the four weeks, it wasn’t surprising to discover that both groups lost a substantial amount of weight. What was surprising: despite similarities in the amount of weight lost, the composition of lean body mass differed substantially between the two groups. The low protein group saw no change in muscle mass while the high protein group added 1.1 kilograms of muscle to their frame. As for fat loss, once again the high protein group posted better numbers, losing 1.3 kilograms more fat than the men who consumed less protein.

As for gains in fitness and strength, they were substantial but not significantly different between the two groups.

Surprised by the results, the McMaster team noted that similar studies haven’t yielded the same success at increasing muscle mass when calories were reduced and exercise (usually weight training) added. In fact, most reported either maintaining or experiencing a small loss of muscle under similar conditions.

The researchers suggest the reason for the difference lies not just in the amount of protein consumed by the young men in the McMaster study, but also in the timing of the protein (immediately after exercise) and in the type of exercise prescribed (strength training complemented with short high intensity intervals).

Before you go out and try to replicate this experiment in hopes of finally fitting into those jeans at the back of the closet, it’s time for a reality check. The diet and exercise routine assumed by both sets of study subjects is more like the gruelling regime featured on The Biggest Loser than that of the average Canadian.

“It wasn’t meant to be sustainable,” said Phillips of the protocols followed in the study. “It was designed to prove a concept.”

Also worthy of note is that the subjects in the study were young men, which means the results don’t automatically apply to women or to anyone middle-aged or beyond. In fact, reviewing the mixed results of similar studies, it’s clear that there’s a high level of sensitivity when it comes to manipulating diet and exercise. A little less protein, a few more calories, a change in gender, a modification in exercise intensity and the results may change.

That said, there is still lots to learn from this study.

“The name of the game is about lowering that loss of muscle mass,” said Phillips who suggests modifying the study’s calorie restriction and exercise protocols so that they are less severe while still maintaining the same breakdown of protein, carbohydrates and fat as the high protein group.

“You have to look long-term,” said Phillips who says losing weight isn’t about who can take off pounds the quickest.

“The dirty little secret about The Biggest Loser is that the winners are always the ones who have lost the most muscle,” said Phillips. “So the winner is actually the biggest loser from a health benefit.”

It’s also the reason so many contestants on the Biggest Loser gain their weight back, which brings us back to where we started. Don’t judge successful weight loss by the numbers on the scale, but by the ability to lose inches without losing muscle.

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